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Fernane and unusually migrated fernane triterpene-triones from Euphorbia supina
m-9422/91 $3.0040.00 0 1990PergamonPressplc
P~yt~~m~stry,Vol. 34 No. 1,pp. 293-296,1991 Printedin Great Britain.
FERNANE AND UNUSUALLY MIGRATED FERNANE TRITERPENE-TRIONES FROM EUPHURBfA SUPIN. REIKO TANAKA
and SHUNYO MATSUNAGA*
Osaka University of Pharmaceutical Sciences, 2-10-65 Kawai, Matsubara, Osaka 580, Japan (Received27 March 1990) Key Word Index-Eupbrbiu supine; Euphorbiaceae; triterpenoids; supinendone D, fern-%en-3,7,11-trione; neospirosupinanetrione; 7(8-+9)ubeo-9R-D:C-fiiedo-B’:A’-neogammaceran-3,7,8-trione.
Abstract-Two new triterpenoids, named supinenolone D and neospirosupinanetrione, have been isolated from the neutral benzene extract of the whole herb of E~~horbiff supina, and their structures determined as fern-g-en-3,7,11trione and 7(X+9)ubeo-BR-D : C-jikM3’ : ~-neogamma~ran-3,7,8-t~one, respectiveiy, on the basis of chemical and spectral evidence.
INTRODIKTION
Previously, we reported the isolation and the structure elucidation of three new fernane type triterpenoids named supinenoiones A (2), B (3) and C (4) [l] and two migrated femane type triterpenoids, named spirosupinanonediol (5) [Z, 33 and neospirosupinanonediol (6) [3], together with fern-8-en-38-01 (1) [4] from the neutral benzene *Author to whom correspondence should be addressed.
1 R’ = P-OH, Rz = 2 R’ = P-OH, R2 = 3 R’ = R3 = @-OH, 4 R’ = P-OH, R’ = 9 R’ = B-OH, R2 =
extract of the whole herb of Euphorbia supina Rafin., a naturalized annual weed which is used as an oriental folk medicine [5]. Because compounds 5 and 6 have unusual skeletal systems of 7(8~9~~beo-D : C-fiiedo-B’ : A’neogammacerane bearing chair-chair conformation of the C/D rings and 7(8-+9)ubeo-9R-D: C-fiiedo-B’ : A’neogammacerane involving boat-chair conformation of the C/D rings, respectively, we proposed the name ‘spirosupinane’ for the former carbon skeleton and ‘neospirosupinane’ for the latter [2,3]. Further examination
0+
R” =
H, a-OH, R3 = 0 R2 = 0 R3 = 0 0, R” = H,
iiT \
7
Ill c
~
0
0
f
293
R. TANAKA and S. MATSUNAGA
294
6
R’=
R’=
r-OH
6a
R’=
R’=
0
-.H
bcr
452.3290). Its UV and IR spectra showed the presence of a transoid ene-dione grouping and a saturated sixmembered ring ketone (A_ 271 nm: v,,, 1710 and 1675 cm-‘). No other absorption bands arising from hydroxyl group or ethylene bond were observed. These facts indicated that the double bond in the ene-dione chromophore was tetrasubstituted. The ‘H and 13C NMR spectra of compound 7 (Tables 1 and 2) revealed the presence of six tertiary and two secondary
of the chemical constituents of this plant led to the isolation of two new t~te~ne-t~ones, named supinenoione D (7) and neospirosupinanetrione (8). This paper deals with the structure elucidation of these compounds. RESULTS AND DISCUSSION
Supinenolone D (7) was assigned the molecular formula of C30H4003 (HRMS: [M]’ at m/z 452.3290; talc:
Table 1. ‘H NMR chemical shifts of compounds 4,Sn, 7 and 8 (300 MHz, CDCl,, TMS as int. standard)* H
4t
7
Sat
8
Me-23 Me-24 Me-25 Me-26 Me-27 Me-28 Me-29
1.02 0.90 I.25 1.27 1.04 0.76 0.84 d
1.11 1.16 1.48 1.29 1.01 0.76 0.84 d
1.16 1.08 0.70 1.11 0.83 0.79 0.83 d
1.15 1.14 0.94 1.05 1.11 0.83 0.83 d
Me-30
(6.5)$ 0.90 d
(6.5) 0.90 d
(6.5) 0.89 d
(6.5) 0.90 d
(6.5)
(6.5) 2.13 m
(6.5) 2.52 m
-
2.81 m
3.29 dd (10.3, 6.2) 2.47 dd (18.5, 8.0) 2.54 dd (18.5, f 1.7) 2.30 d (18.7) 2.19d (18.7)
-
(6.5) 2.34 ddd (15.0, 8.3,4.6) 2.92 ddd (15.0, 11.0, 7.0) -
2
3a 6ci 68 12a 128
2.51 dd (18.5, 8.0) 2.60 dd (18.5, 11.7) 2.31 d (18.7) 2.19d (18.7)
*Assi~ments were made by 2D ‘H-‘H ‘H-W COSY experiments. tData taken from refs [I, 43. $J(Hz) in parentheses.
2.16 dd (18.9, 11.8) 2.46 dd (18.9, 10.4) -
2.76 ddd (13.5, 11.0, 5.5) 2.31 dd (19.5, 8.5) 2.41 dd (19.5, 12.6)
COSY, 2D zH-‘3C COSY and 20 long range
Triterpenoidsfrom ~up~r&ia supina
295
Table 2. 13CNMR chemicalshiftsof compounds 4, %I, 7 and 8 in (74.5 MHz, CDC13, TMS as int. standard)* C
4t
7
W
8
1 2 3 4 5 6 7
34.42 27.43 78.06 38.64 47.97 36.70 199.99 151.92 156.01 38.16 201.14 51.14 38.47 41.59 26.41 35.80 42.57 50.80 20.40 28.93 59.54 30.66 27.51 14.87 17.93 21.87 20.79 14.02 22.90 22.03
35.17 34.28 214.14 47.10 49.15 36.98 198.81 151.35 154.83 37.99 201.11 50.92 41.82 38.42 26.36 35.74 42.48 50.72 20.37 27.88 59.49 30.60 24.76 21.22 17.34 21.82 20.68 13.99 22.87 22.00
29.33 34.46 213.74 46.55 44.48 33.68 217.69 209.69 72.30 48.78 25.42 30.10 40.16 55:95 26.50 34.81 42.77 51.59 19.50 28.15 59.63 30.63 29.70 20.93 18.72 17.33 15.73 15.13 22.84 21.92
32.76 34.45 215.86 46.25 48.33 37.01 217.49 213.34 70.11 47.80 26.93 30.52 40.07 51.82 25.63 34.75 42.91 51.37 19.51 28.17 59.77 30.63 29.06 20.56 20.56 15.96 15.29 15.18 22.85 21.95
a
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
*Assignments were made by 20 ‘H-‘H COSY, 2D ‘H-13C COSY and 2D long range lH-13C COSY experiments. TData taken from refs [1,43.
methyl groups, three methylene groups adjacent to carbony1 groups [S, 2.19-2.81 (6H)] and a tetrasubstituted double bond [Sc 151.35 and 154.83 (each s)] as well as three keto-groups (Sc 198.81,201.11 and 214.14). In the EI mass spectrum, compound 7 displayed four predominant fragment ion peaks characteristic for the cleavage of
spectrum revealed three predominant ion peaks attributable to the cleavage of ring C at m/z 247 (ion b), 234 (ion c) and 220 (ion d), respectively, besides peaks at m/z 303 (ion
fern-8-en-7,l l-dione derivatives at m/z382.2504 (ion a), 367.2269 (ion b), 299.1653 (ion c), 288.1729 (ion d), 287.1643 (ion e), 275.1648 (ion f), 248.1410 (ion g) and 205.1953 (ion h), together with a fragment ion peak at m/z409.2745 [M -isopropyl group] + [ 1J. These facts indicated that compound 7 was probably fem-l-en3,7,11-trione. Conclusive evidence for the structure was obtained by the synthesis of this compound Oxidation of naturally occurring supinenolone C (4) with chromium trioxide in pyridine furnished fern-8-en-3,7,11-trione, which was identical in all respects with 7. Compound 8 had the molecular formula of C3,,H460s (HRMS: [M] + at m/z454.3446; talc: 454.3447). Its IR spectrum showed absorption bands for one fivemembered and two six-membered ring ketones In the ‘H and tvln,, 1752, 1713 and 1678cm-‘). 13C NMR spectra (Tables 1 and 2), it exhibited signals for six angular methyl groups, one isopropyl group and three keto-groups. No other signals arising from hydroxyl
a) and 205 (ion e) [2, 31. The former three peaks have never been observed in the spectra of compounds 5,6 and all their acetates except for their trioxo-derivatives, spir(5a) and neospirosupinanetrione @a), osupinanetrione which have previously been synthesized by chromium trioxide oxidation of 5 and 6 in pyridine, respectively [Z, 33. Physical and all the spectral data of compound 8 were very similar with those of 6a rather than those of Sa, and the structure was finally confirmed by direct comparison of 8 with 6a. This is the first report of the isolation of compounds 7 and 8 from natural sources. The co-existence of 7 and 8 together with compounds l-6 in E. supine enable the const~~ion of plausible biosynthetic pathways for compounds 2-g from fern&en-3&ol(l) via 3#I-hydroxy-fem8-en-7-one (9). Although we have not yet isolated 9 from this plant, it can be considered to play an important role in the formation of both 7 and 8. Compounds 4 and 7 may be produced by further enzymatic oxidation of the allylic
groups or olefhric protons were observed. The DEPT subspectrum indicated that it must have the same carbon skeleton as that of either 5 or 6. Furthermore, the El mass
296
R. TANAKA and S. MATSUNAGA
C-l 1 methylene group, compound 9 by oxidation of both the C-11 methylene group and the C-3 hydroxyl group in compound 9, while compound 8 may be derived by either epoxidation of the As-double bond in 9 and subsequent cleavage of the epoxy-ring involving transformation of the C-7/C-8 bond to the C-9 position or by Baeyer-Villigar oxidation of 9 [6], followed by the cleavage of the resulting lactone ring involving retro-aldolizaseems to contain peculiar and very tion. Thus, E. supina active enzymes which bring about the oxidation or oxidative rearrangement of fern-8-en-3/?-01(l) around the centre of its carbon skeleton to give highly oxygenated fern-8-enes, spirosupinane and its analogues.
EXPERIMENTAL General. Mps: uncorr. Optical rotation: CHCI,. UV: EtOH; IR: KBr discs. ‘H NMR (300 MHz) and 13C NMR (74.5 MHz): CDCI, with TMS as int. standard. EIMS: 70 eV (probe); TLC: silica gel HF,,, (0.25 mm, Merck) and CC: silica gel 60 (7&230 mesh, Merck). Preliminary CC of the neutral CsHs Isolation ofcompounds. extract (1.15 kg) of the dried whole herb of E. supina (10 kg) has already been reported [l, 73. Repeated silica gel CC (80 g) of the resinous product (791 mg), which has been collected from the frs just before elution of supinenolone C with C,H&HCl, (5: l-3: 1) in the preliminary CC [l], furnished p-alnincanol (217 mg) and 17B,21fi-epoxyhopan-3p-ol (425 mg), as has previously been reported [7], from the frs eluted with a mixt. of C,H,-CHCl, (5: 1), successively. Further elution with a mixt. of C,H,&HCl, (3: 1) afforded compounds 7 (16 mg) and 8 (27 mg), respectively. Supinenolone D (7). Yellow prisms, mp 209-211” (MeOH-CHCl,), [a]? - 21.3” (CHCI,; c 0.49); R, 0.45 (plate: 0.25 mm thick, solvent: C,H,-EtOAc, 5:l); HRMS: [M]’ at m/z 452.3290 (C 30H 44 0 3 requires 452.3290); UV AZ:” 271 nm (E 8600) [transoid ene-dione]; IR ~5:; cm-‘: 2960, 2942, 2865, 1710 (C=O), 1675 (O=&&=&A=O), 1467, 1384, 1223, 1120, 1018,1006 and 943; ‘H and 13C NMR: see Tables 1 and 2; EIMS: m/z (rel. int.) 452 (100) [Ml’, 437 (68) [M-Me]+, 424 (9) [M -CO]‘, 409 (11), [M-C3H7]+, 382 (28) [ion a], 367 (21) [ion b], 299 (5) [ion c], 288 (30) [ion d], 287 (12) [ion e], 275 (47) [ion f], 248 (15) [ion g], 205 (11) [ion h] and 201 (15). Synthesis offern-8-en-3,7,11-trione. To a soln of supinenolone C (4) (25 mg) in pyridine (3 ml) was added a soln of CrO, (30 mg)
in pyridine (5 ml) containing two drops of H,O at 0” and the mixt. was stirred at room temp. for 10 hr. Evapn of the pyridine from the mixt. in uacuo gave a residue, which was dissolved with Et,0 (20 ml) and the Et,0 soln was washed successively with 5% NaHSO, soln and H,O and then dried with Na,SO,. Removal of the solvent afforded a yellow solid (26 mg), which was purified by prep. TLC (C,H,CHCl,-EtOAc, 2:2: 1) to give fern-8-en-3,7,11-trione (23 mg), mp 208-211” (MeOH-CHCl,). It was identified by direct comparison (mmp, co-TLC, UV, IR, ‘H NMR, 13C NMR and EIMS) with supinenolone D (7). Neospirosupinanetrione (8). Prisms, mp 290-292.5” (MeOH-CHCI,), [ali +4.8” (CHCI,; ~0.37) (lit. [3] mp 290-292”, [ali f4.8” (CHCl,; c 0.37); R, 0.40 (C,H,-EtOAc, 5: 1); HRMS: [M]’ at m/z 454.3446 (C JOH 460 3 requires 454.3447); IR ~5:; cm- I: 2948, 2870, 1752 (5-membered ring C=O), 1713 and 1678 (each 6-membered ring C=O), 1465,1389, 1370, 1245, 1177, 1138, 1120, 1018 and 952; ‘H and 13CNMR: see Tables 1 and 2; EIMS: m/z (rel. int.) 454 (17) [Ml’, 439 (15) [M-Me]+,426(9) [M-CO]+,411 (14) [M-C,H,]+, 383(35) [M-CO-C,H,]+, 303 (14) [ion a], 247 (9) [ion b], 234 (48) [ion c], 220 (95) [ion d] and 205 (100) [ion e]. Compound 8 was identified by direct comparison (mmp, co-TLC, IR, ‘H and 13C NMR, and EIMS) with the trione (6a) prepared from 6 [3].
Acknowledgement-The Yoneda, an ex-member ments.
authors are indebted to of this University, for NMR
Mrs M. measure-
REFERENCES 1. Tanaka, R. and Matsunaga, S. (1989) Phytochemistry 28, 3149. 2. Matsunaga, S., Morita, R., Ishida, T., Inoue, M. Shigi, M. and Miyamae, A. (1984) J. Chem. Sot., Chem. Commun. 1128. S., Nishino, H. and 3. Tanaka, R., In, Y., Ishida, T., Matsunaga, Iwashima, A. (1990) J. Chem. Sot., Perkin Trans I (in press). 4. Tanaka, R. and Matsunaga, S. (1988) Phytochemistry 27, 3579. 5. Nanba, T. and Mikage, M. (1983) Poisonous Plants, p. 74. Hoiku-sha, Osaka. 6. Bass, W. J. (1985) Phytochemistry 24, 1875. 7. Tanaka, R., Kurimoto, M., Yoneda, M. and Matsunaga, S. (1990) Phytochemistry 29, 2253.
P~yt~~m~stry,Vol. 34 No. 1,pp. 293-296,1991 Printedin Great Britain.
FERNANE AND UNUSUALLY MIGRATED FERNANE TRITERPENE-TRIONES FROM EUPHURBfA SUPIN. REIKO TANAKA
and SHUNYO MATSUNAGA*
Osaka University of Pharmaceutical Sciences, 2-10-65 Kawai, Matsubara, Osaka 580, Japan (Received27 March 1990) Key Word Index-Eupbrbiu supine; Euphorbiaceae; triterpenoids; supinendone D, fern-%en-3,7,11-trione; neospirosupinanetrione; 7(8-+9)ubeo-9R-D:C-fiiedo-B’:A’-neogammaceran-3,7,8-trione.
Abstract-Two new triterpenoids, named supinenolone D and neospirosupinanetrione, have been isolated from the neutral benzene extract of the whole herb of E~~horbiff supina, and their structures determined as fern-g-en-3,7,11trione and 7(X+9)ubeo-BR-D : C-jikM3’ : ~-neogamma~ran-3,7,8-t~one, respectiveiy, on the basis of chemical and spectral evidence.
INTRODIKTION
Previously, we reported the isolation and the structure elucidation of three new fernane type triterpenoids named supinenoiones A (2), B (3) and C (4) [l] and two migrated femane type triterpenoids, named spirosupinanonediol (5) [Z, 33 and neospirosupinanonediol (6) [3], together with fern-8-en-38-01 (1) [4] from the neutral benzene *Author to whom correspondence should be addressed.
1 R’ = P-OH, Rz = 2 R’ = P-OH, R2 = 3 R’ = R3 = @-OH, 4 R’ = P-OH, R’ = 9 R’ = B-OH, R2 =
extract of the whole herb of Euphorbia supina Rafin., a naturalized annual weed which is used as an oriental folk medicine [5]. Because compounds 5 and 6 have unusual skeletal systems of 7(8~9~~beo-D : C-fiiedo-B’ : A’neogammacerane bearing chair-chair conformation of the C/D rings and 7(8-+9)ubeo-9R-D: C-fiiedo-B’ : A’neogammacerane involving boat-chair conformation of the C/D rings, respectively, we proposed the name ‘spirosupinane’ for the former carbon skeleton and ‘neospirosupinane’ for the latter [2,3]. Further examination
0+
R” =
H, a-OH, R3 = 0 R2 = 0 R3 = 0 0, R” = H,
iiT \
7
Ill c
~
0
0
f
293
R. TANAKA and S. MATSUNAGA
294
6
R’=
R’=
r-OH
6a
R’=
R’=
0
-.H
bcr
452.3290). Its UV and IR spectra showed the presence of a transoid ene-dione grouping and a saturated sixmembered ring ketone (A_ 271 nm: v,,, 1710 and 1675 cm-‘). No other absorption bands arising from hydroxyl group or ethylene bond were observed. These facts indicated that the double bond in the ene-dione chromophore was tetrasubstituted. The ‘H and 13C NMR spectra of compound 7 (Tables 1 and 2) revealed the presence of six tertiary and two secondary
of the chemical constituents of this plant led to the isolation of two new t~te~ne-t~ones, named supinenoione D (7) and neospirosupinanetrione (8). This paper deals with the structure elucidation of these compounds. RESULTS AND DISCUSSION
Supinenolone D (7) was assigned the molecular formula of C30H4003 (HRMS: [M]’ at m/z 452.3290; talc:
Table 1. ‘H NMR chemical shifts of compounds 4,Sn, 7 and 8 (300 MHz, CDCl,, TMS as int. standard)* H
4t
7
Sat
8
Me-23 Me-24 Me-25 Me-26 Me-27 Me-28 Me-29
1.02 0.90 I.25 1.27 1.04 0.76 0.84 d
1.11 1.16 1.48 1.29 1.01 0.76 0.84 d
1.16 1.08 0.70 1.11 0.83 0.79 0.83 d
1.15 1.14 0.94 1.05 1.11 0.83 0.83 d
Me-30
(6.5)$ 0.90 d
(6.5) 0.90 d
(6.5) 0.89 d
(6.5) 0.90 d
(6.5)
(6.5) 2.13 m
(6.5) 2.52 m
-
2.81 m
3.29 dd (10.3, 6.2) 2.47 dd (18.5, 8.0) 2.54 dd (18.5, f 1.7) 2.30 d (18.7) 2.19d (18.7)
-
(6.5) 2.34 ddd (15.0, 8.3,4.6) 2.92 ddd (15.0, 11.0, 7.0) -
2
3a 6ci 68 12a 128
2.51 dd (18.5, 8.0) 2.60 dd (18.5, 11.7) 2.31 d (18.7) 2.19d (18.7)
*Assi~ments were made by 2D ‘H-‘H ‘H-W COSY experiments. tData taken from refs [I, 43. $J(Hz) in parentheses.
2.16 dd (18.9, 11.8) 2.46 dd (18.9, 10.4) -
2.76 ddd (13.5, 11.0, 5.5) 2.31 dd (19.5, 8.5) 2.41 dd (19.5, 12.6)
COSY, 2D zH-‘3C COSY and 20 long range
Triterpenoidsfrom ~up~r&ia supina
295
Table 2. 13CNMR chemicalshiftsof compounds 4, %I, 7 and 8 in (74.5 MHz, CDC13, TMS as int. standard)* C
4t
7
W
8
1 2 3 4 5 6 7
34.42 27.43 78.06 38.64 47.97 36.70 199.99 151.92 156.01 38.16 201.14 51.14 38.47 41.59 26.41 35.80 42.57 50.80 20.40 28.93 59.54 30.66 27.51 14.87 17.93 21.87 20.79 14.02 22.90 22.03
35.17 34.28 214.14 47.10 49.15 36.98 198.81 151.35 154.83 37.99 201.11 50.92 41.82 38.42 26.36 35.74 42.48 50.72 20.37 27.88 59.49 30.60 24.76 21.22 17.34 21.82 20.68 13.99 22.87 22.00
29.33 34.46 213.74 46.55 44.48 33.68 217.69 209.69 72.30 48.78 25.42 30.10 40.16 55:95 26.50 34.81 42.77 51.59 19.50 28.15 59.63 30.63 29.70 20.93 18.72 17.33 15.73 15.13 22.84 21.92
32.76 34.45 215.86 46.25 48.33 37.01 217.49 213.34 70.11 47.80 26.93 30.52 40.07 51.82 25.63 34.75 42.91 51.37 19.51 28.17 59.77 30.63 29.06 20.56 20.56 15.96 15.29 15.18 22.85 21.95
a
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
*Assignments were made by 20 ‘H-‘H COSY, 2D ‘H-13C COSY and 2D long range lH-13C COSY experiments. TData taken from refs [1,43.
methyl groups, three methylene groups adjacent to carbony1 groups [S, 2.19-2.81 (6H)] and a tetrasubstituted double bond [Sc 151.35 and 154.83 (each s)] as well as three keto-groups (Sc 198.81,201.11 and 214.14). In the EI mass spectrum, compound 7 displayed four predominant fragment ion peaks characteristic for the cleavage of
spectrum revealed three predominant ion peaks attributable to the cleavage of ring C at m/z 247 (ion b), 234 (ion c) and 220 (ion d), respectively, besides peaks at m/z 303 (ion
fern-8-en-7,l l-dione derivatives at m/z382.2504 (ion a), 367.2269 (ion b), 299.1653 (ion c), 288.1729 (ion d), 287.1643 (ion e), 275.1648 (ion f), 248.1410 (ion g) and 205.1953 (ion h), together with a fragment ion peak at m/z409.2745 [M -isopropyl group] + [ 1J. These facts indicated that compound 7 was probably fem-l-en3,7,11-trione. Conclusive evidence for the structure was obtained by the synthesis of this compound Oxidation of naturally occurring supinenolone C (4) with chromium trioxide in pyridine furnished fern-8-en-3,7,11-trione, which was identical in all respects with 7. Compound 8 had the molecular formula of C3,,H460s (HRMS: [M] + at m/z454.3446; talc: 454.3447). Its IR spectrum showed absorption bands for one fivemembered and two six-membered ring ketones In the ‘H and tvln,, 1752, 1713 and 1678cm-‘). 13C NMR spectra (Tables 1 and 2), it exhibited signals for six angular methyl groups, one isopropyl group and three keto-groups. No other signals arising from hydroxyl
a) and 205 (ion e) [2, 31. The former three peaks have never been observed in the spectra of compounds 5,6 and all their acetates except for their trioxo-derivatives, spir(5a) and neospirosupinanetrione @a), osupinanetrione which have previously been synthesized by chromium trioxide oxidation of 5 and 6 in pyridine, respectively [Z, 33. Physical and all the spectral data of compound 8 were very similar with those of 6a rather than those of Sa, and the structure was finally confirmed by direct comparison of 8 with 6a. This is the first report of the isolation of compounds 7 and 8 from natural sources. The co-existence of 7 and 8 together with compounds l-6 in E. supine enable the const~~ion of plausible biosynthetic pathways for compounds 2-g from fern&en-3&ol(l) via 3#I-hydroxy-fem8-en-7-one (9). Although we have not yet isolated 9 from this plant, it can be considered to play an important role in the formation of both 7 and 8. Compounds 4 and 7 may be produced by further enzymatic oxidation of the allylic
groups or olefhric protons were observed. The DEPT subspectrum indicated that it must have the same carbon skeleton as that of either 5 or 6. Furthermore, the El mass
296
R. TANAKA and S. MATSUNAGA
C-l 1 methylene group, compound 9 by oxidation of both the C-11 methylene group and the C-3 hydroxyl group in compound 9, while compound 8 may be derived by either epoxidation of the As-double bond in 9 and subsequent cleavage of the epoxy-ring involving transformation of the C-7/C-8 bond to the C-9 position or by Baeyer-Villigar oxidation of 9 [6], followed by the cleavage of the resulting lactone ring involving retro-aldolizaseems to contain peculiar and very tion. Thus, E. supina active enzymes which bring about the oxidation or oxidative rearrangement of fern-8-en-3/?-01(l) around the centre of its carbon skeleton to give highly oxygenated fern-8-enes, spirosupinane and its analogues.
EXPERIMENTAL General. Mps: uncorr. Optical rotation: CHCI,. UV: EtOH; IR: KBr discs. ‘H NMR (300 MHz) and 13C NMR (74.5 MHz): CDCI, with TMS as int. standard. EIMS: 70 eV (probe); TLC: silica gel HF,,, (0.25 mm, Merck) and CC: silica gel 60 (7&230 mesh, Merck). Preliminary CC of the neutral CsHs Isolation ofcompounds. extract (1.15 kg) of the dried whole herb of E. supina (10 kg) has already been reported [l, 73. Repeated silica gel CC (80 g) of the resinous product (791 mg), which has been collected from the frs just before elution of supinenolone C with C,H&HCl, (5: l-3: 1) in the preliminary CC [l], furnished p-alnincanol (217 mg) and 17B,21fi-epoxyhopan-3p-ol (425 mg), as has previously been reported [7], from the frs eluted with a mixt. of C,H,-CHCl, (5: 1), successively. Further elution with a mixt. of C,H,&HCl, (3: 1) afforded compounds 7 (16 mg) and 8 (27 mg), respectively. Supinenolone D (7). Yellow prisms, mp 209-211” (MeOH-CHCl,), [a]? - 21.3” (CHCI,; c 0.49); R, 0.45 (plate: 0.25 mm thick, solvent: C,H,-EtOAc, 5:l); HRMS: [M]’ at m/z 452.3290 (C 30H 44 0 3 requires 452.3290); UV AZ:” 271 nm (E 8600) [transoid ene-dione]; IR ~5:; cm-‘: 2960, 2942, 2865, 1710 (C=O), 1675 (O=&&=&A=O), 1467, 1384, 1223, 1120, 1018,1006 and 943; ‘H and 13C NMR: see Tables 1 and 2; EIMS: m/z (rel. int.) 452 (100) [Ml’, 437 (68) [M-Me]+, 424 (9) [M -CO]‘, 409 (11), [M-C3H7]+, 382 (28) [ion a], 367 (21) [ion b], 299 (5) [ion c], 288 (30) [ion d], 287 (12) [ion e], 275 (47) [ion f], 248 (15) [ion g], 205 (11) [ion h] and 201 (15). Synthesis offern-8-en-3,7,11-trione. To a soln of supinenolone C (4) (25 mg) in pyridine (3 ml) was added a soln of CrO, (30 mg)
in pyridine (5 ml) containing two drops of H,O at 0” and the mixt. was stirred at room temp. for 10 hr. Evapn of the pyridine from the mixt. in uacuo gave a residue, which was dissolved with Et,0 (20 ml) and the Et,0 soln was washed successively with 5% NaHSO, soln and H,O and then dried with Na,SO,. Removal of the solvent afforded a yellow solid (26 mg), which was purified by prep. TLC (C,H,CHCl,-EtOAc, 2:2: 1) to give fern-8-en-3,7,11-trione (23 mg), mp 208-211” (MeOH-CHCl,). It was identified by direct comparison (mmp, co-TLC, UV, IR, ‘H NMR, 13C NMR and EIMS) with supinenolone D (7). Neospirosupinanetrione (8). Prisms, mp 290-292.5” (MeOH-CHCI,), [ali +4.8” (CHCI,; ~0.37) (lit. [3] mp 290-292”, [ali f4.8” (CHCl,; c 0.37); R, 0.40 (C,H,-EtOAc, 5: 1); HRMS: [M]’ at m/z 454.3446 (C JOH 460 3 requires 454.3447); IR ~5:; cm- I: 2948, 2870, 1752 (5-membered ring C=O), 1713 and 1678 (each 6-membered ring C=O), 1465,1389, 1370, 1245, 1177, 1138, 1120, 1018 and 952; ‘H and 13CNMR: see Tables 1 and 2; EIMS: m/z (rel. int.) 454 (17) [Ml’, 439 (15) [M-Me]+,426(9) [M-CO]+,411 (14) [M-C,H,]+, 383(35) [M-CO-C,H,]+, 303 (14) [ion a], 247 (9) [ion b], 234 (48) [ion c], 220 (95) [ion d] and 205 (100) [ion e]. Compound 8 was identified by direct comparison (mmp, co-TLC, IR, ‘H and 13C NMR, and EIMS) with the trione (6a) prepared from 6 [3].
Acknowledgement-The Yoneda, an ex-member ments.
authors are indebted to of this University, for NMR
Mrs M. measure-
REFERENCES 1. Tanaka, R. and Matsunaga, S. (1989) Phytochemistry 28, 3149. 2. Matsunaga, S., Morita, R., Ishida, T., Inoue, M. Shigi, M. and Miyamae, A. (1984) J. Chem. Sot., Chem. Commun. 1128. S., Nishino, H. and 3. Tanaka, R., In, Y., Ishida, T., Matsunaga, Iwashima, A. (1990) J. Chem. Sot., Perkin Trans I (in press). 4. Tanaka, R. and Matsunaga, S. (1988) Phytochemistry 27, 3579. 5. Nanba, T. and Mikage, M. (1983) Poisonous Plants, p. 74. Hoiku-sha, Osaka. 6. Bass, W. J. (1985) Phytochemistry 24, 1875. 7. Tanaka, R., Kurimoto, M., Yoneda, M. and Matsunaga, S. (1990) Phytochemistry 29, 2253.